#include "crc_verify.h"

const uint16_t crc16_table_CCITT [256]={
        0x0000,0x1189,0x2312,0x329B,0x4624,0x57AD,0x6536,0x74BF,
        0x8C48,0x9DC1,0xAF5A,0xBED3,0xCA6C,0xDBE5,0xE97E,0xF8F7,
        0x1081,0x0108,0x3393,0x221A,0x56A5,0x472C,0x75B7,0x643E,
        0x9CC9,0x8D40,0xBFDB,0xAE52,0xDAED,0xCB64,0xF9FF,0xE876,
        0x2102,0x308B,0x0210,0x1399,0x6726,0x76AF,0x4434,0x55BD,
        0xAD4A,0xBCC3,0x8E58,0x9FD1,0xEB6E,0xFAE7,0xC87C,0xD9F5,
        0x3183,0x200A,0x1291,0x0318,0x77A7,0x662E,0x54B5,0x453C,
        0xBDCB,0xAC42,0x9ED9,0x8F50,0xFBEF,0xEA66,0xD8FD,0xC974,
        0x4204,0x538D,0x6116,0x709F,0x0420,0x15A9,0x2732,0x36BB,
        0xCE4C,0xDFC5,0xED5E,0xFCD7,0x8868,0x99E1,0xAB7A,0xBAF3,
        0x5285,0x430C,0x7197,0x601E,0x14A1,0x0528,0x37B3,0x263A,
        0xDECD,0xCF44,0xFDDF,0xEC56,0x98E9,0x8960,0xBBFB,0xAA72,
        0x6306,0x728F,0x4014,0x519D,0x2522,0x34AB,0x0630,0x17B9,
        0xEF4E,0xFEC7,0xCC5C,0xDDD5,0xA96A,0xB8E3,0x8A78,0x9BF1,
        0x7387,0x620E,0x5095,0x411C,0x35A3,0x242A,0x16B1,0x0738,
        0xFFCF,0xEE46,0xDCDD,0xCD54,0xB9EB,0xA862,0x9AF9,0x8B70,
        0x8408,0x9581,0xA71A,0xB693,0xC22C,0xD3A5,0xE13E,0xF0B7,
        0x0840,0x19C9,0x2B52,0x3ADB,0x4E64,0x5FED,0x6D76,0x7CFF,
        0x9489,0x8500,0xB79B,0xA612,0xD2AD,0xC324,0xF1BF,0xE036,
        0x18C1,0x0948,0x3BD3,0x2A5A,0x5EE5,0x4F6C,0x7DF7,0x6C7E,
        0xA50A,0xB483,0x8618,0x9791,0xE32E,0xF2A7,0xC03C,0xD1B5,
        0x2942,0x38CB,0x0A50,0x1BD9,0x6F66,0x7EEF,0x4C74,0x5DFD,
        0xB58B,0xA402,0x9699,0x8710,0xF3AF,0xE226,0xD0BD,0xC134,
        0x39C3,0x284A,0x1AD1,0x0B58,0x7FE7,0x6E6E,0x5CF5,0x4D7C,
        0xC60C,0xD785,0xE51E,0xF497,0x8028,0x91A1,0xA33A,0xB2B3,
        0x4A44,0x5BCD,0x6956,0x78DF,0x0C60,0x1DE9,0x2F72,0x3EFB,
        0xD68D,0xC704,0xF59F,0xE416,0x90A9,0x8120,0xB3BB,0xA232,
        0x5AC5,0x4B4C,0x79D7,0x685E,0x1CE1,0x0D68,0x3FF3,0x2E7A,
        0xE70E,0xF687,0xC41C,0xD595,0xA12A,0xB0A3,0x8238,0x93B1,
        0x6B46,0x7ACF,0x4854,0x59DD,0x2D62,0x3CEB,0x0E70,0x1FF9,
        0xF78F,0xE606,0xD49D,0xC514,0xB1AB,0xA022,0x92B9,0x8330,
        0x7BC7,0x6A4E,0x58D5,0x495C,0x3DE3,0x2C6A,0x1EF1,0x0F78
};

uint16_t crc16_CCITT(uint8_t* datas,uint16_t len){
    uint16_t crc_value = 0;
    while (len--){
        crc_value = (crc_value >> 8) ^ crc16_table_CCITT[(crc_value ^ *datas++) & 0xff];
    }
    return crc_value;
}

uint16_t crc16_CCITT(char *data, uint16_t len)
{
    uint8_t* datas = reinterpret_cast<unsigned char*>(data);
    uint16_t crc_value = 0;
    while (len--){
        crc_value = (crc_value >> 8) ^ crc16_table_CCITT[(crc_value ^ *datas++) & 0xff];
    }
    return crc_value;
}

bool check_CCITT(char *data, uint16_t len)
{
    uint16_t result = crc16_CCITT(data, len - 2);
    uint8_t temp1, temp2;
    temp1 = result >> 8;
    temp2 = result & 0xff;
    temp1 = temp1 ^ (data[len - 2] & 0xff);
    temp2 = temp2 ^ (data[len - 1] & 0xff);
    if(temp1 == 0 && temp2 == 0)
        return false;
    else
        return true;
}
